Outline emerges of last moments before Asiana plane crash in San Francisco

Deborah Hersman of the National Transportation Safety Board speaks in front of a photograph of Asiana Flight 214, which crashed on Saturday, July 6, 2013, at San Francisco International Airport, at a news conference in South San Francisco, Calif., Thursday, July 11, 2013.

Jeff Chiu, Associated Press

“The first thing that's taught to a pilot is to look at the airspeed indicator. It is the most important instrument in the cockpit.”

Lee Collins

SAN FRANCISCO — Nearly a week after Asiana Flight 214 collided with a rocky seawall just short of its intended airport runway, investigators have pieced together an outline of the event — what should have been a smooth landing by seasoned pilots turning into a disaster.

With each new bit of information, the picture emerging is of pilots who were supposed to be closely monitoring the plane's airspeed, but who didn't realize until too late that the aircraft was dangerously low and slow. Nothing disclosed so far by the National Transportation Safety Board investigators indicates any problems with the Boeing 777's engines or the functioning of its computers and automated systems.

"The first thing that's taught to a pilot is to look at the airspeed indicator. It is the most important instrument in the cockpit," said Lee Collins, a pilot with 29 years and 18,000 hours experience flying a variety of airliners. "Airspeed is everything. You have airspeed, you live. You don't, you die."

Investigators are still trying to nail down hundreds of details about the crash last Saturday that killed two people and injured dozens. NTSB Chairman Deborah Hersman has cautioned against reaching conclusions.

But investigators already know a great deal. They've listened to the Boeing 777's voice recorder, which captured the last two hours of conversation in the cockpit. They've downloaded its flight data recorder, which captured 1,400 indicators of what was happening on the plane, from the temperatures inside and out to the positions of cockpit instruments.

The flight's four pilots have been interviewed, as have passengers and dozens of witnesses. Air traffic control recordings and video of the flight's last moments, including the crash itself, have been examined.

Here's what investigators have revealed about a Seoul-to-San Francisco flight that was normal until its last minutes, when the wide-body jet carrying 307 people rapidly lost altitude:

The pilot flying the plane, Lee Gang-kuk, 46, had nearly 10,000 hours of flying experience, but just 35 hours flying a Boeing 777. He had recently completed training that qualified him to fly passengers in the 777, and was about halfway through his post-qualification training. He was seated in the left cockpit pilot seat. In the co-pilot position was Lee Jeong-Min, an experienced captain who was supervising Lee Gang-kuk's training. It was Lee Gang-kuk's first time landing a 777 in San Francisco.

At 11:19:23 PDT, after a nearly 11-hour flight, the plane was traveling over the San Francisco Peninsula. The weather was near perfect, sunny with light winds.

Lee Jeong-Min and a third pilot sitting in a jump seat just behind the main seats, a first officer, were supposed to be monitoring the plane's controls. One of their most important jobs was to closely monitor the plane's two airspeed indicators. In the U.S., if an amber bar is more than five knots above or below the target speed during landing, the pilot flying is supposed to abort and make another attempt, according to pilots interviewed by The Associated Press.

As the plane descended to 1,600 feet, the autopilot was turned off. At 1,400 feet, the plane's airspeed was about 170 knots.

The flight data recorder shows the plane's autothrottle — similar to a car's cruise control — was set on idle during the approach, Hersman said, and that there were multiple commands at times given to the autothrottle and autopilot.

At 11:26:58 and 1,000 feet, the pilots made contact with the airport tower. When they were cleared to land 12 seconds later, the plane's altitude had dropped to about 600 feet. The plane was configured for its approach and the landing gear was down. The airspeed was about 149 knots. A target speed of 137 knots was set.

At 500 feet there was an audible automated altitude alert. The airspeed was about 134 knots. At this point that pilots realized they weren't properly lined up with the runway, Hersman said.